According to the state of the art different kind of batteries in various forms are known, each of which is designed and used for different technical applications. In particular in the field of medical devices batteries must be small and their outside be made of biocompatible materials. However the batteries must show high energy density and long life cycles.
Batteries with a small structure are for example button batteries, which usually comprise a cup-shaped housing with a cover part. The anode and cathode materials are housed within the cup and separated by a separator from each other. The cup is covered by the cover part, wherein a sealing is located between the cup and the cover to provide a gas tight interior space. The sealing usually is provided by a rubber or plastic ring or the like. The cup and the cover respectively comprise electrical connectors to connect the button battery to an electrical circuit or consumer load. Such button batteries for example are known from EP 0 615 301 B1 (Alliant Techsystems) or US 2003/0162436 A1 (Denso Corp.). In other designs, where contacts to both electrodes are provided on the same side of the battery, an insulated feed-through such as a glass duct is needed. The provision of sealings and required separations of electrodes within the battery or the feed-through itself require a lot of space. Therefore the architecture of common button batteries mostly is bulky. Also the available space is not fully used to optimize energy density of the battery.
Other small batteries are for example thin film batteries as described in US 2006/0154141 A1 (R. Salot et al.). These batteries are produced by a thin film technique which e.g. first etches a battery space in a substrate and then builds up the battery layer by layer. Production of such batteries is very costly and time consuming.